1. Did it (the chord trainer app) help my son when he was studying music? Not as far as I can tell. He has also been taking piano lessons and sometimes it helps a little with music theory to tie it back to the chords, but I don't think there's much transfer learning going on. He seems to have a good ear, but my other son is not picking up chords nearly as quickly, and I know a bunch of other kids have bounced off this app, so my older son may just already naturally have a good ear.

2. Did it (studying music) help my son (with identifying chords)? I don't think so. He made pretty steady progress in the chords before he started piano, and after he started piano it didn't get any easier. He also mentions things like, "The chords sound different on the piano", which makes me think I need to have more varied samples (even though the book says that consistency is key and you should practice on the same piano holding the chords for the same duration every time).